从xml文件中删除指定的节点，问题是多次删除操作只有最后一次删除操作才是真正执行的，问下代码哪里有问题？
XML code:
<?xml version="1.0" encoding="UTF-8"?>
<ip-config>
<ip>
<host>221.214.208.17</host>
<port>3128</port>
</ip>
<ip>
<host>222.76.210.8</host>
<port>8080</port>
</ip>
<ip>
<host>222.89.92.106</host>
<port>3128</port>
</ip>
<ip>
<host>218.90.171.249</host>
<port>8080</port>
</ip>
<ip>
<host>218.201.21.177</host>
<port>80</port>
</ip>
<ip>
<host>221.130.13.39</host>
<port>80</port>
</ip>
<ip>
<host>221.130.13.37</host>
<port>80</port>
</ip>
<ip>
<host>221.130.13.232</host>
<port>80</port>
</ip>
<ip>
<host>221.130.13.228</host>
<port>80</port>
</ip>
<ip>
<host>221.130.13.42</host>
<port>80</port>
&
如何对xml内容数据进行比较
例如：
<?xml version='1.0' encoding='utf-8'?>
<TestLIST>
<PID>40</PID>
<TestName>深圳市</TestName>
......
